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Korean J Parasitol > Volume 21(2):1983 > Article

Original Article
Korean J Parasitol. 1983 Dec;21(2):135-141. English.
Published online Mar 20, 1994.  http://dx.doi.org/10.3347/kjp.1983.21.2.135
Copyright © 1983 by The Korean Society for Parasitology
Epidemiological studies on Ascaris lumbricoides reinfection in rural communities in Korea 1. The relationship between prevalence and monthly reinfection rate
Jong-Yil Chai
Department of Parasitology and Institute of Endemic Diseases, College of Medicine, Seoul National University, Korea.
Abstract

The epidemiological relationship between the current prevalence and monthly reinfection rate of Ascaris lumbricoides was observed in rural communities in Korea by measns of blanket mass chemotherapy and worm collection for measurement of the prevalence and reinfection rates. During the period from 1975 to 1980, a total of 4,466 inhabitants in 10 different localities were treated with 10 mg/kg of pyrantel pamoate and 2 days' whole stools were collected from 2,547 inhabitants. The stools were examined for the presence of expelled adult and/or young worms, which represent the prevalence and reinfection rates for past 2 months respectively. After then, the obtained rates were correlated each other applying the time-prevalence curve proposed by Hayashi.

It was observed that the prevalence (overall worm positive rate) and worm burden per individual ranged by areas from 13.6 to 72.3% and 1.4-10.2 respectively. The calculated monthly reinfection rates (X) (from young worm positive rates) according to areas were in the range, 2.6~16.2%, and clearly correlated with the current prevalence (Y) under the equation, Y=1-(1-X)7.2 where 7.2 is time in month. The equation means that after one time mass chemotherapy the period needed to attain equilibrium of prevalence again would be about 7~8 months. And it is inferred that the majority of reinfected worms in human host turn over every 7~8 months.

Figures


Fig. 1
Regression curve, Y=1-(1-X)N, between prevalence (Y) and monthly reinfection rate (X) of A. lumbricoides, where 'N' is the constant value (6, 7.2 or 9) of time in month.


Fig. 2
Time-prevalence curves when monthly reinfection rates are variable. The equation is Y=1-(1-X)N, where 'Y' is the prevalence and 'N' is time in month. (A) Continuous elevation of prevalence so far as the equation is concerned, (B) Suggested feature of maintenance of equilibrium in prevalence after 7~8 months. (a) when monthly reinfection rate (X) is 20%, (b) X=15%, (c) X=10%, (d) X=5% and (e) X=2%.

Tables


Table 1
The results of worm collection study of A. lumbricoides in various areas, Korea (1975~'80)


Table 2
Young worm positive rate and monthly reinfection rate of A. lumbricoides

References
1. Anderson RM, May RM. Population dynamics of human helminth infections: control by chemotherapy. Nature 1982;297(5867):557–563.
  
2. Arfaa F, Ghadirian E. Epidemiology and mass-treatment of ascariasis in six rural communities in central Iran. Am J Trop Med Hyg 1977;26(5 Pt 1):866–871.
 
3. Cabrera BD, Arambulo PV 3rd, Portillo GP. Ascariasis control and/or eradication in a rural community in the Philippines. Southeast Asian J Trop Med Public Health 1975;6(4):510–518.
 
4. Cho SY. Study on the quantitative evaluation of reinfection of Ascaris lumbricoides. Korean J Parasitol 1977;15(1):17–29.
 
5. Croll NA, Anderson RM, Gyorkos TW, Ghadirian E. The population biology and control of Ascaris lumbricoides in a rural community in Iran. Trans R Soc Trop Med Hyg 1982;76(2):187–197.
  
6. Kozai I. Jpn J Parasit 1962;11:400–410.
7. Lechat MF, Jancloes MF, Galambos F, Cornet P, Thienpont D. Control by levamisole of ascariasis and ancylostomiasis in rural areas. Trop Geogr Med 1974;26(4):441–445.
 
8. Matsuzaki G, et al. Jap J Sanitary Animal 1954;4:139–149.
9. Morishita K. Progress of Medical Parasit in Japan 1972;5:145–213.
10. Pan CT, Ritchie LS, Hunter GW 3rd. Reinfection and seasonal fluctuations of Ascaris lumbricoides among a group of children in an area where night soil is used. J Parasitol 1954;40(5, Part 1):603–608.
  
11. Rim HJ, Lim JK. Treatment of enterobiasis and ascariasis with Combantrin (pyrantel pamoate). Trans R Soc Trop Med Hyg 1972;66(1):170–175.
  
12. Seo BS. Collected Papers on the Control of Soil-transmitted Helminthiases (by APCO Research Group) 1983;11:194–216.
13. Seo BS, Chai JY. Chronologic Growth Pattern Of Ascaris lumbrioides. Korean J Parasitol 1980;18(2):164–170.
 
14. Seo BS, Chai JY. Effect Of Two-Month Interval Mass Chemotherapy On The Reinfection Of Ascaris Lumbricoides In Korea. Korean J Parasitol 1980;18(2):153–163.
 
15. Seo BS, Cho SY, Chai JY. Frequency Distribution Of Ascaris Lumbricoides In Rural Koreans With Special Reference On The Effect Of Changing Endemicity. Korean J Parasitol 1979;17(2):105–113.
 
16. Seo BS, Cho SY, Chai JY, Hong ST. Comparative Efficacy Of Interval Mass Treatment On Ascaris Lumbricoides Infection In Korea. Korean J Parasitol 1980;18(2):145–151.
 
17. Seo BS, et al. Korean Central J Med 1972;23:579–584.
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